Hach-Lange ORBISPHERE 510_51x Basic User Manual - Manual (Page 19)

Note: The temperature sensor is factory calibrated and can only be changed by a Hach Lange representative.
Definitions
To calibrate the gas to measure (main gas), the user usually puts the sensor in the main gas without
any interfering gas.
Calibrations can only be performed once the instrument has been installed, configured and each
channel has been set up. You must also ensure that you have the correct access rights to access the
calibration menu.
Select sensor calibration from the calibration menu, then select the channel to calibrate.
There are two types of gas sensor calibration available, depending on the gas being measured and
the type of sensor being used:
1. In Air: For Oxygen and Ozone with an EC sensor.
2. Direct value: Any gas with either an EC or TC sensor. This calibration exposes the sensor to a
gas with a known partial pressure, or a liquid sample with a known gas concentration.
EC gas sensor calibration
Calibration of the measured gas
1. Before initiating a calibration process, the calibration parameters must be set by pressing on the
Modify button. The last calibration parameters are memorized, so this step can be ignored if the
correct parameters are already set.
Option Description
Calibration mode
• Direct value: Any gas
• In Air (default): For O
2
or O
3
Medium Select liquid or gas (direct calibration only)
Concentration unit type Partial, fraction or dissolved (dissolved is for calibration in a liquid only)
Concentration unit The list of available units depends on unit type selected above.
Liquid Select as appropriate, available when liquid has been selected in medium
(above).
Value Enter the gas concentration according to the value in the calibration media, when
direct value is used.
Hold during calibration On by default, this stops any output from the instrument during the calibration
process to avoid sending invalid information to any connected device.
Interference enabled If selected, this takes into account the influence of interferences during calibration.
By default the same interference as during measurement is selected.
2. Press OK to start calibration
• A calibration screen will be displayed showing current measurement data which is continually
refreshed.
• The value “% ideal current” is a percentage of the current against the ideal current for the
membrane type selected. If this percentage is not within the accepted range, an error message
is displayed and the calibration process fails. A warning message can be displayed when this
value is close to the boundaries, but when calibration can be accepted.
• The message is first displayed in the result box. The dialog box with the error message or the
warning is displayed when the finish button is pressed.
• The value “% last calibration” shows the ratio between the current measurement and the
previous sensor calibration.
• The value “% variation” indicates the variation during the last 3 measurements, which is the
stability of the measurements. A variation as low as possible is needed for a precise
calibration.
English 19